Servicing database requests using subsets of canonicalized tables

ABSTRACT

Servicing database requests using subsets of canonicalized tables including maintaining a canonical table repository of canonicalized tables, wherein each canonicalized table is a transformed version of a table previously retrieved from a database; receiving, from a client computing system, a request for a table from the database; generating a description of a canonical version of the requested table; determining that the canonical version of the requested table is a subset of a canonicalized table in the canonical table repository; and in response to determining that the canonical version of the requested table is a subset of the canonicalized table in the canonical table repository: transforming the canonicalized table containing a superset of the canonical version of the requested table based on the received request for the table; and providing, to the client computing system, the transformed canonicalized table containing the superset of the canonical version of the requested table.

CROSS-REFERENCE TO RELATED APPLICATION

This application is a non-provisional application for patent entitled to a filing date and claiming the benefit of earlier-filed U.S. Provisional Patent Application Ser. No. 62/867,493, filed Jun. 27, 2019.

BACKGROUND Field of the Invention

The field of the invention is data processing, or, more specifically, methods, apparatus, and products for servicing database requests using subsets of canonicalized tables.

Description of Related Art

Modern businesses may store large amounts of data in remote databases within cloud-based data warehouses. This data may be accessed using database query languages, such as structured query language (SQL). Manipulating the data stored in the database may require constructing complex queries beyond the abilities of most users. Further, each query issued to the cloud-based data warehouse may incur a cost and require time to wait for the response.

SUMMARY

Methods, systems, and apparatus for servicing database requests using subsets of canonicalized tables. Servicing database requests using subsets of canonicalized tables includes maintaining a canonical table repository of canonicalized tables, wherein each canonicalized table is a transformed version of a table previously retrieved from a database; receiving, from a client computing system, a request for a table from the database; generating a description of a canonical version of the requested table; determining that the canonical version of the requested table is a subset of a canonicalized table in the canonical table repository; and in response to determining that the canonical version of the requested table is a subset of the canonicalized table in the canonical table repository: transforming the canonicalized table containing a superset of the canonical version of the requested table based on the received request for the table; and providing, to the client computing system, the transformed canonicalized table containing the superset of the canonical version of the requested table.

The foregoing and other objects, features and advantages of the invention will be apparent from the following more particular descriptions of exemplary embodiments of the invention as illustrated in the accompanying drawings wherein like reference numbers generally represent like parts of exemplary embodiments of the invention.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 sets forth a block diagram of an example system configured for servicing database requests using subsets of canonicalized tables according to embodiments of the present invention.

FIG. 2 sets forth a block diagram of an example system configured for servicing database requests using subsets of canonicalized tables according to embodiments of the present invention.

FIG. 3 sets forth a block diagram of an example system configured for servicing database requests using subsets of canonicalized tables according to embodiments of the present invention.

FIG. 4 sets forth a flow chart illustrating an exemplary method for servicing database requests using subsets of canonicalized tables according to embodiments of the present invention.

FIG. 5 sets forth a flow chart illustrating an exemplary method for servicing database requests using subsets of canonicalized tables according to embodiments of the present invention.

FIG. 6 sets forth a flow chart illustrating an exemplary method for servicing database requests using subsets of canonicalized tables according to embodiments of the present invention.

DETAILED DESCRIPTION

Exemplary methods, apparatus, and products for servicing database requests using subsets of canonicalized tables in accordance with the present invention are described with reference to the accompanying drawings, beginning with FIG. 1. FIG. 1 sets forth a block diagram of automated computing machinery comprising an exemplary evaluation engine computing system (152) configured for servicing database requests using subsets of canonicalized tables according to embodiments of the present invention. The evaluation engine computing system (152) of FIG. 1 includes at least one computer processor (156) or ‘CPU’ as well as random access memory (168) (RAM′) which is connected through a high speed memory bus (166) and bus adapter (158) to processor (156) and to other components of the evaluation engine computing system (152).

Stored in RAM (168) is an operating system (154). Operating systems useful in computers configured for servicing database requests using subsets of canonicalized tables according to embodiments of the present invention include UNIX™, Linux™, Microsoft Windows™, AIX™, IBM's iOS™, and others as will occur to those of skill in the art. The operating system (154) in the example of FIG. 1 is shown in RAM (168), but many components of such software typically are stored in non-volatile memory also, such as, for example, on data storage (170), such as a disk drive. Also stored in RAM is the evaluation engine (126), a module for servicing database requests using subsets of canonicalized tables according to embodiments of the present invention.

The evaluation engine computing system (152) of FIG. 1 includes disk drive adapter (172) coupled through expansion bus (160) and bus adapter (158) to processor (156) and other components of the evaluation engine computing system (152). Disk drive adapter (172) connects non-volatile data storage to the evaluation engine computing system (152) in the form of data storage (170). Disk drive adapters useful in computers configured for servicing database requests using subsets of canonicalized tables according to embodiments of the present invention include Integrated Drive Electronics (‘IDE’) adapters, Small Computer System Interface (‘SCSI’) adapters, and others as will occur to those of skill in the art. Non-volatile computer memory also may be implemented for as an optical disk drive, electrically erasable programmable read-only memory (so-called ‘EEPROM’ or ‘Flash’ memory), RAM drives, and so on, as will occur to those of skill in the art.

The example evaluation engine computing system (152) of FIG. 1 includes one or more input/output (‘I/O’) adapters (178). I/O adapters implement user-oriented input/output through, for example, software drivers and computer hardware for controlling output to display devices such as computer display screens, as well as user input from user input devices (181) such as keyboards and mice. The example evaluation engine computing system (152) of FIG. 1 includes a video adapter (209), which is an example of an I/O adapter specially designed for graphic output to a display device (180) such as a display screen or computer monitor. Video adapter (209) is connected to processor (156) through a high speed video bus (164), bus adapter (158), and the front side bus (162), which is also a high speed bus.

The exemplary evaluation engine computing system (152) of FIG. 1 includes a communications adapter (167) for data communications with other computers and for data communications with a data communications network. Such data communications may be carried out serially through RS-232 connections, through external buses such as a Universal Serial Bus (‘USB’), through data communications networks such as IP data communications networks, and in other ways as will occur to those of skill in the art. Communications adapters implement the hardware level of data communications through which one computer sends data communications to another computer, directly or through a data communications network. Examples of communications adapters useful in computers configured for servicing database requests using subsets of canonicalized tables according to embodiments of the present invention include modems for wired dial-up communications, Ethernet (IEEE 802.3) adapters for wired data communications, and 802.11 adapters for wireless data communications.

The communications adapter (167) is communicatively coupled to a wide area network (190) that also includes a cloud-based data warehouse (192) and a client system (194). The cloud-based data warehouse (192) is a computing system or group of computing systems that hosts a database for access over the wide area network (190). The client system (194) is a computing system that accesses the database using the evaluation engine (126) on the evaluation engine computing system (152).

FIG. 2 shows an exemplary system for servicing database requests using subsets of canonicalized tables according to embodiments of the present invention. As shown in FIG. 2, the system includes a client computing system (194), an evaluation engine computing system (152), and a cloud-based data warehouse (192). The client computing system (194) includes a graphical user interface (GUI) (202). The evaluation engine computing system (152) includes an evaluation engine (126) and a canonical table repository (204). The cloud-based data warehouse (192) includes a database (206).

The GUI (202) is a visual presentation configured to present tables in the form of worksheets and graphical elements to a user. The GUI (202) also receives requests from a user for tables from the database (206). The GUI (202) may be presented, in part, by the evaluation engine (126) and displayed on a client computing system (194) (e.g., on a system display or mobile touchscreen). The GUI (202) may be part of an Internet application that includes the evaluation engine (126) and is hosted on the evaluation engine computing system (152).

The database (206) is a collection of data and a management system for the data. A table is a collection of data from the database (206). Tables may be organizations of data sets generated in response to a database query and provided to the evaluation engine (126). Tables include data sets organized into columns and rows. The particular columns, rows, and organization of the columns and rows that make up a table may be specified in the database query requesting the table. A table, as sent from the database to the evaluation engine (126) and client computing system (194), may be a portion or subset of a source database table on the database.

The evaluation engine (126) is hardware, software, or an aggregation of hardware and software configured to receive requests from the client computing system (194), via the GUI (GUI). The evaluation engine (126) is also configured to generate database queries in response to requests for data sets and manipulations of those data sets. The evaluation engine (126) may be part of a database query generator that generates the database query.

The canonical table repository (204) is an aggregation of hardware and software used to store canonicalized tables. A canonicalized table is a version of a table configured for comparison and matching to another table or a portion of another table. Canonicalized tables may be used to determine if one table includes the same root data set as, or superset of, another table (or group of tables) stored in the canonical table repository (204). Canonicalized tables may arrange the columns and rows in a particular order that differs from the order of columns and rows in the associated table as presented in a worksheet for the user or as stored as the source database table in the database. Further, canonicalized tables may have mutable labels or information in the table (e.g., column and row titles) converted to absolute location information (e.g., column or row number of the source database table).

For example, a user may request a table that includes a particular arrangement of the first ten rows and first ten columns from a database table. The evaluation engine (126) may convert the requested table into a description of the canonicalized version of the table that has a different arrangement of the same ten rows and ten columns form the database table. The evaluation engine (126) may then search the canonical table repository (204) for a canonicalized table that includes at least the canonicalized version of the requested table. If a canonicalized table exists that includes at least the canonicalized version of the requested table, then the evaluation engine (126) extracts the canonicalized version of the requested table and manipulates the canonicalized table into the requested table without having to issue a database query to the database. If a canonicalized table does not exist that includes the canonicalized version of the requested table, then the evaluation engine (126) issues a database query to the database, receives the requested table, provides the requested table to the user, then converts the requested table into a canonicalized table and stores the table in the canonical table repository (204). Accordingly, each table retrieved from the database (or the most recent tables) are stored as canonicalized versions in the canonical table repository (204). The manner in which the received tables are converted into canonical version may be referred to as the canonical conversion policy.

As a specific example, assume that the evaluation engine (126) retrieves the following table from a database that lists the populations of New York, Michigan, Washington, Minnesota, Idaho, New Hampshire, Maine, Montana, North Dakota, and Vermont in the years 2016, 2017, and 2018, and sorted from largest to smallest population in 2018. Table 1 shows the retrieved and presented table.

TABLE 1 State 2016 2017 2018 New York 19,641,589 19,590,719 19,542,209 Michigan 9,951,890 9,976,447 9,995,915 Washington 7,294,680 7,425,432 7,535,591 Minnesota 5,523,409 5,568,155 5,611,179 Idaho 1,682,930 1,718,904 1,754,208 New Hampshire 1,342,373 1,349,767 1,356,458 Maine 1,331,370 1,335,063 1,338,404 Montana 1,040,863 1,053,090 1,062,305 North Dakota 754,353 755,176 760,077 Vermont 623,644 624,525 626,299

Upon receiving the above table from the database, the evaluation engine may convert the table to a canonicalized table by removing the row column labels and resorting the rows base on the row location in the source database table. Table 2 shows the resulting canonicalized table.

TABLE 2 Col: 8 Col: 9 Col: 10 Row: 14 1,682,930 1,718,904 1,754,208 Row: 21 1,331,370 1,335,063 1,338,404 Row: 24 9,951,890 9,976,447 9,995,915 Row: 25 5,523,409 5,568,155 5,611,179 Row: 28 1,040,863 1,053,090 1,062,305 Row: 31 1,342,373 1,349,767 1,356,458 Row: 34 19,641,589 19,590,719 19,542,209 Row: 36 754,353 755,176 760,077 Row: 47 623,644 624,525 626,299 Row: 49 7,294,680 7,425,432 7,535,591

The canonical conversion policy may convert two different tables into identical canonicalized tables. Similarly, two different requests for tables from the database may result in the same canonicalized table being used to satisfy both requests. For example, a user may issue a first request for a table with a particular arrangement of rows and columns, and issue a second request for a different arrangement of the same rows and columns. The same canonical table may be used to satisfy both requests, although it will be transformed differently depending on the specific request.

FIG. 3 shows an exemplary system for servicing database requests using subsets of canonicalized tables according to embodiments of the present invention. As shown in FIG. 3, the exemplary GUI (202) includes a spreadsheet structure (302), a list structure (304), and an exposable parameter (306). The spreadsheet structure (302) includes a worksheet (shown as empty rows) with six columns (column A (306A), column B (306B), column C (306C), column D (306D), column E (306E), column F (306F)).

The spreadsheet structure (302) is a graphical element and organizing mechanism for a worksheet that presents a table. A worksheet is a presentation of a table from a database (204). The spreadsheet structure (302) displays the worksheet as rows of data organized by columns (column A (306A), column B (306B), column C (306C), column D (306D), column E (306E), column F (306F)). The columns delineate different categories of the data in each row of the worksheet. The columns may also be calculations using other columns in the worksheet.

The list structure (304) is a graphical element used to define and organize the hierarchical relationships between the columns (column A (306A), column B (306B), column C (306C), column D (306D), column E (306E), column F (306F)) of the data set. The term “hierarchical relationship” refers to subordinate and superior groupings of columns. For example, a database may include rows for an address book, and columns for state, county, city, and street. A data set from the database may be grouped first by state, then by county, and then by city. Accordingly, the state column would be at the highest level in the hierarchical relationship, the county column would be in the second level in the hierarchical relationship, and the city column would be at the lowest level in the hierarchical relationship.

The list structure (304) presents a dimensional hierarchy to the user. Specifically, the list structure (304) presents levels arranged hierarchically across at least one dimension. Each level within the list structure (304) is a position within a hierarchical relationship between columns (column A (306A), column B (306B), column C (306C), column D (306D), column E (306E), column F (306F)). The keys within the list structure (304) identify the one or more columns that are the participants in the hierarchical relationship. Each level may have more than one key.

One of the levels in the list structure (304) may be a base level. Columns selected for the base level provide data at the finest granularity. One of the levels in the list structure (304) may be a totals or root level. Columns selected for the totals level provide data at the highest granular level. For example, the totals level may include a field that calculates the sum of each row within a single column of the entire data set (i.e., not partitioned by any other column).

The GUI (202) may enable a user to drag and drop columns (column A (306A), column B (306B), column C (306C), column D (306D), column E (306E), column F (306F)) into the list structure (304). The order of the list structure (304) may specify the hierarchy of the columns relative to one another. A user may be able to drag and drop the columns in the list structure (304) at any time to redefine the hierarchical relationship between columns. The hierarchical relationship defined using the columns selected as keys in the list structure (304) may be utilized in charts such that drilling down (e.g., double click on a bar), enables a new chart to be generated based on a level lower in the hierarchy.

The GUI (202) may also include a mechanism for a user to request a table from a database to be presented as a worksheet in the GUI (202). Such a mechanism may be part of the interactivity of the worksheet. Specifically, a user may manipulate a worksheet (e.g., by dragging and dropping columns or rows, resorting columns or rows, etc.) and, in response, the GUI (202) may generate request (e.g., in the form of a state specification) for a table and send the request to the evaluation engine (126). Such a mechanism may also include a direct identification of the rows and columns of a database table that a user would like to access (e.g., via a selection of the rows and columns in a dialog box).

For further explanation, FIG. 4 sets forth a flow chart illustrating an exemplary method for servicing database requests using subsets of canonicalized tables according to embodiments of the present invention that includes maintaining (402) a canonical table repository (204) of canonicalized tables, wherein each canonicalized table is a transformed version of a table previously retrieved from a database. Maintaining (402) a canonical table repository (204) of canonicalized tables, wherein each canonicalized table is a transformed version of a table previously retrieved from a database may be carried out by the evaluation engine (126) converting each table received from the database into a canonicalized table and storing the canonicalized table in the canonical table repository (204). Maintaining (402) a canonical table repository (204) of canonicalized tables may also include removing canonicalized tables to make space available for new canonicalized tables. This may be performed based on a removal policy, such as removing tables that have not been accessed in the longest period of time.

The canonicalized tables within the canonical table repository (204) may be indexed by worksheet specifications describing each canonicalized table. Specifically, each canonicalized table may be associated with a worksheet specification that describes the canonicalized table. Each worksheet specification may describe the source database table, rows, and columns of the associated canonicalized table. For example, a database may include a source database table referred to as “state_ceensus_50yrs” that includes census data for each state from 2010 to 2018. A table retrieved from the database may have the columns for 2014, 2015, and 2016, and the rows for Alabama, Florida, Louisiana, Mississippi, and Texas. The worksheet specification may include the name of the source data worksheet and a description of the 2014, 2015, and 2016 columns and the Alabama, Florida, Louisiana, Mississippi, and Texas rows. In a canonical description, the worksheet specification may be “dbtable:state_census_50yr; col: 6, 7, 8; row: 2, 11, 20, 26, 45”. The worksheet specification may then be used to match a similar description of a requested table to a canonicalized table stored in the canonical table repository (204).

The method of FIG. 4 further includes receiving (404), from a client computing system (194), a request (420) for a table from the database. Receiving (404), from a client computing system (194), a request (420) for a table from the database may be carried out by the evaluation engine (126) detecting, via a GUI, that a user has manipulated a worksheet or other element displayed within a GUI on the client computing system (194). Such manipulations may include dragging and dropping columns or rows, resorting columns or rows, or identifying rows and columns of a database table that the user would like to access (e.g., via a selection of the rows and columns in a dialog box). In response, the GUI may generate the request (420) (e.g., in the form of a state specification) for a table and send the request to the evaluation engine (126).

The method of FIG. 4 further includes generating (406) a description of a canonical version of the requested table. Generating (406) a description of a canonical version of the requested table may be carried out by the evaluation engine (126) evaluating the request (420) and converting the request (420) into a form to be used to attempt to match the requested table to a canonical table in the canonical table repository (204). The description of a canonical version of the requested table may be in the form of a worksheet specification as described above.

The method of FIG. 4 further includes determining (408) that the canonical version of the requested table is a subset of a canonicalized table in the canonical table repository (204). Determining (408) that the canonical version of the requested table is a subset of a canonicalized table in the canonical table repository (204) may be carried out by the evaluation engine (126) determining that the canonical version of the requested table does not match any canonicalized table in the canonical table repository. Specifically, the evaluation engine (126) may first determine whether the canonical version of the requested table matches exactly a canonicalized table in the canonical table repository (204). If no exact match exists, then the evaluation engine (126) determines whether a canonicalized table in the canonical table repository (204) includes the canonical version of the requested table (i.e., the canonical version of the requested table is a subset of a canonicalized table in the canonical table repository (204)).

Determining (408) that the canonical version of the requested table is a subset of a canonicalized table in the canonical table repository (204) may further be carried out by the evaluation engine (126) evaluating each canonicalized table in the canonical table repository (204) to determine whether any canonicalized table includes the rows and columns of the canonical version of the requested table. For example, a user may request Table 3 below from the evaluation engine (126).

TABLE 3 State 2017 2018 New York 19,590,719 19,542,209 New Hampshire 1,349,767 1,356,458 Maine 1,335,063 1,338,404 Vermont 624,525 626,299

The request may identify columns 2017 and 2018 and rows New York, New Hampshire, Maine, and Vermont, ordered from largest to smallest value in column 2018. Upon receiving the request for Table 3, the evaluation engine (126) generates a description of the canonical version of the requested table, as shown in Table 4.

TABLE 4 Col: 9 Col: 10 Row: 21 1,335,063 1,338,404 Row: 31 1,349,767 1,356,458 Row: 34 19,590,719 19,542,209 Row: 47 624,525 626,299

The evaluation engine (126) would not generate Table 4 because the evaluation engine does not yet have access to the values at each row-column intersection. Rather, the evaluation engine (126) generates a description of the canonical version of the requested table. Such a description may be a worksheet specification such as “dbtable:state_census_50yr; col: 9, 10; row: 21, 31, 34, 47”. If no exact match to the requested table exists in the canonical table repository (204), then the evaluation engine (126) determines whether the canonical version of the requested table is a subset of a canonicalized table in the canonical table repository (204). Specifically, the evaluation engine (126) determines whether any canonicalized table in the canonical table repository (204) includes columns 9 and 10, and rows 21, 31, 34, and 47. If Table 2 is in the canonical table repository (204), then the evaluation engine would determine that canonicalized Table 2 includes each column and row of the requested table.

The method of FIG. 4 further includes in response (410) to determining that the canonical version of the requested table is a subset of the canonicalized table in the canonical table repository (204): transforming (412) the canonicalized table containing a superset of the canonical version of the requested table based on the received request for the table; and providing (414), to the client computing system (194), the transformed canonicalized table containing the superset of the canonical version of the requested table.

Transforming (412) the canonicalized table containing a superset of the canonical version of the requested table based on the received request for the table may be carried out by the evaluation engine (126) repositioning columns and rows in the canonicalized table to match the requested table. Transforming (412) the canonicalized table containing a superset of the canonical version of the requested table based on the received request for the table may also be carried out by replacing the column and row identifiers with labels based on the requested table. Specifically, the user may include, in the request, an ordering of the rows or columns, such as an ordering based on values in the columns and rows. The user may also include, in the request, a renaming of columns or rows from the label used in the source database table. Accordingly, the column and/or rows may be renamed based on the requested table.

Providing (414), to the client computing system (194), the transformed canonicalized table containing the superset of the canonical version of the requested table may be carried out by the evaluation engine (126) presenting, via the GUI on the client computing system (194), the transformed canonicalized table containing the superset of the canonical version of the requested table as a worksheet to the user. Providing (414), to the client computing system (194), the transformed canonicalized table containing the superset of the canonical version of the requested table may bypass retrieving the requested table from the database. Specifically, because the table or tables were retrieved locally from the canonical table repository (204), no request or transfer between the evaluation engine (126) and the cloud-based data warehouse (192) was required. The requested table is provided without involving the database on the cloud-based data warehouse (192).

If the evaluation engine (126) determines that the canonical version of the requested table does not match or is not a subset of any canonicalized table in the canonical table repository (204), then the evaluation engine (126) generates a database query using the request for the table from the database; issues the database query to the database; receives, from the database, the requested table; provides, to the client computing system (194), the requested table from the database; converts the requested table into a canonical version of the requested table; and stores the canonical version of the requested table in the canonical table repository (204).

Generating a database query using the request for the table from the database may be carried out by the evaluation engine (126) using the request (420) to populate the database query targeting the database on the cloud-based data warehouse (192). The database query may be an SQL statement. Issuing the database query to the database may be carried out by the evaluation engine (126) sending the generated database query over a wide area network to the database on the cloud-based data warehouse (192).

Receiving, from the database, the requested table may be carried out by the evaluation engine (126) receiving a database query response that includes the requested table from the database. The received table may be in a form that matches or largely matches the requested table. Once received, the table may undergo some conversion to a form that matches the requested table and prepares the received table for presentation to the client as a worksheet. Providing, to the client computing system (194), the requested table from the database may be carried out by the evaluation engine (126) presenting, via the GUI on the client computing system (194), the received table as a worksheet to the user.

Converting the requested table into a canonical version of the requested table may be carried out by the evaluation engine (126) altering the requested (and received) table based on the canonical conversion policy. Converting the requested table into the canonical version of the requested table may include altering column and/or row labels and reordering one or more columns and/or rows. Storing the canonical version of the requested table in the canonical table repository (204) may be carried out by the evaluation engine (126) generating a worksheet specification for the canonicalize table and storing the canonicalized table in the canonical table repository (204) indexed by the generated worksheet specification.

The above limitations improve the operation of the computer system by servicing table requests from a user without issuing a query to a database and without the increased latency of database interaction. This is accomplished by retrieving previously received tables from a local canonical table repository (204). Further, because the tables are stored as canonicalized versions of the tables, more requested tables will match subsets of previously stored table than if the tables were stored in the form as received from the database.

For further explanation, FIG. 5 sets forth a flow chart illustrating a further exemplary method for servicing database requests using subsets of canonicalized tables according to embodiments of the present invention that includes maintaining (402) a canonical table repository (204) of canonicalized tables, wherein each canonicalized table is a transformed version of a table previously retrieved from a database; receiving (404), from a client computing system (194), a request (420) for a table from the database; generating (406) a description of a canonical version of the requested table; determining (408) that the canonical version of the requested table is a subset of a canonicalized table in the canonical table repository (204); and in response (410) to determining that the canonical version of the requested table is a subset of the canonicalized table in the canonical table repository (204): transforming (412) the canonicalized table containing a superset of the canonical version of the requested table based on the received request for the table; and providing (414), to the client computing system (194), the transformed canonicalized table containing the superset of the canonical version of the requested table.

The method of FIG. 5 differs from the method of FIG. 4, however, in that determining (408) that the canonical version of the requested table is a subset of a canonicalized table in the canonical table repository (204) includes matching (502) each column and row in the canonical version of the requested table to columns and rows in the canonicalized table in the canonical table repository (204). Matching (502) each column and row in the canonical version of the requested table to columns and rows in the canonicalized table in the canonical table repository (204) may be carried out by the evaluation engine (126) searching the canonical table repository (204) (e.g., using the worksheet specifications for each canonicalized table) for each column and each row in the description for the canonical version of the requested table. If a canonicalized table exists with each row and each column, then a match exists that contains at least the subset of columns and rows in the description for the canonical version of the requested table.

The method of FIG. 5 further differs from the method of FIG. 4, however, in that transforming (412) the canonicalized table containing a superset of the canonical version of the requested table based on the received request for the table includes extracting (504) the subset of the canonicalized table in the canonical table repository (204) to generate the requested table. Extracting (504) the subset of the canonicalized table in the canonical table repository (204) to generate the requested table may be carried out by the evaluation engine (126) copying, to a new table, the rows and columns from the canonicalized table that match the rows and columns from the description of the canonical version of the requested table. The evaluation engine (126) may then alter the new table as described in the request (420) for the table from the database.

For further explanation, FIG. 6 sets forth a flow chart illustrating a further exemplary method for servicing database requests using subsets of canonicalized tables according to embodiments of the present invention that includes maintaining (402) a canonical table repository (204) of canonicalized tables, wherein each canonicalized table is a transformed version of a table previously retrieved from a database; receiving (404), from a client computing system (194), a request (420) for a table from the database; generating (406) a description of a canonical version of the requested table; determining (408) that the canonical version of the requested table is a subset of a canonicalized table in the canonical table repository (204); and in response (410) to determining that the canonical version of the requested table is a subset of the canonicalized table in the canonical table repository (204): transforming (412) the canonicalized table containing a superset of the canonical version of the requested table based on the received request for the table; and providing (414), to the client computing system (194), the transformed canonicalized table containing the superset of the canonical version of the requested table.

The method of FIG. 6 differs from the method of FIG. 4, however, in that determining (408) that the canonical version of the requested table is a subset of a canonicalized table in the canonical table repository (204) includes determining (602) that the canonical version of the requested table is a subset of a combination of at least two canonicalized tables in the canonical table repository (204). Specifically, the evaluation engine (126) may determine whether the description of the canonical version of the requested table may be satisfied using a combination of more than one canonicalized table in the canonical table repository (204).

For example, assume that the canonical table repository (204) includes two tables with the worksheet descriptions “dbtable:state_census_50yr; col: 8, 9, 10; row: 14, 21, 24, 25, 28” and “dbtable:state_census_50yr; col: 8, 9, 10; row: 31, 34, 36, 47, 49”. If the user requests Table 3, above, with the converted worksheet description “dbtable:state_census_50yr; col: 9, 10; row: 21, 31, 34, 47”, then the evaluation engine (126) will determine that the request can be satisfied using both table “dbtable:state_census_50yr; col: 8, 9, 10; row: 14, 21, 24, 25, 28” and table “dbtable:state_census_50yr; col: 8, 9, 10; row: 31, 34, 36, 47, 49”. In other words, the requested table “dbtable:state_census_50yr; col: 9, 10; row: 21, 31, 34, 47” is a subset of the combination of canonical table repository (204) tables “dbtable:state_census_50yr; col: 8, 9, 10; row: 14, 21, 24, 25, 28” and “dbtable:state_census_50yr; col: 8, 9, 10; row: 31, 34, 36, 47, 49”.

In view of the explanations set forth above, readers will recognize that the benefits of servicing database requests using subsets of canonicalized tables according to embodiments of the present invention include:

-   -   Improving the operation of a computing system by servicing         database requests using a local repository and without issuing a         query to a database, increasing computing system efficiency.     -   Improving the operation of a computing system by servicing         database requests without the increased latency of database         interaction, increasing computing system responsiveness.

Exemplary embodiments of the present invention are described largely in the context of a fully functional computer system for servicing database requests using subsets of canonicalized tables. Readers of skill in the art will recognize, however, that the present invention also may be embodied in a computer program product disposed upon computer readable storage media for use with any suitable data processing system. Such computer readable storage media may be any storage medium for machine-readable information, including magnetic media, optical media, or other suitable media. Examples of such media include magnetic disks in hard drives or diskettes, compact disks for optical drives, magnetic tape, and others as will occur to those of skill in the art. Persons skilled in the art will immediately recognize that any computer system having suitable programming means will be capable of executing the steps of the method of the invention as embodied in a computer program product. Persons skilled in the art will recognize also that, although some of the exemplary embodiments described in this specification are oriented to software installed and executing on computer hardware, nevertheless, alternative embodiments implemented as firmware or as hardware are well within the scope of the present invention.

The present invention may be a system, a method, and/or a computer program product. The computer program product may include a computer readable storage medium (or media) having computer readable program instructions thereon for causing a processor to carry out aspects of the present invention.

The computer readable storage medium can be a tangible device that can retain and store instructions for use by an instruction execution device. The computer readable storage medium may be, for example, but is not limited to, an electronic storage device, a magnetic storage device, an optical storage device, an electromagnetic storage device, a semiconductor storage device, or any suitable combination of the foregoing. A non-exhaustive list of more specific examples of the computer readable storage medium includes the following: a portable computer diskette, a hard disk, a random access memory (RAM), a read-only memory (ROM), an erasable programmable read-only memory (EPROM or Flash memory), a static random access memory (SRAM), a portable compact disc read-only memory (CD-ROM), a digital versatile disk (DVD), a memory stick, a floppy disk, a mechanically encoded device such as punch-cards or raised structures in a groove having instructions recorded thereon, and any suitable combination of the foregoing. A computer readable storage medium, as used herein, is not to be construed as being transitory signals per se, such as radio waves or other freely propagating electromagnetic waves, electromagnetic waves propagating through a waveguide or other transmission media (e.g., light pulses passing through a fiber-optic cable), or electrical signals transmitted through a wire.

Computer readable program instructions described herein can be downloaded to respective computing/processing devices from a computer readable storage medium or to an external computer or external storage device via a network, for example, the Internet, a local area network, a wide area network and/or a wireless network. The network may comprise copper transmission cables, optical transmission fibers, wireless transmission, routers, firewalls, switches, gateway computers and/or edge servers. A network adapter card or network interface in each computing/processing device receives computer readable program instructions from the network and forwards the computer readable program instructions for storage in a computer readable storage medium within the respective computing/processing device.

Computer readable program instructions for carrying out operations of the present invention may be assembler instructions, instruction-set-architecture (ISA) instructions, machine instructions, machine dependent instructions, microcode, firmware instructions, state-setting data, or either source code or object code written in any combination of one or more programming languages, including an object oriented programming language such as Smalltalk, C++ or the like, and conventional procedural programming languages, such as the “C” programming language or similar programming languages. The computer readable program instructions may execute entirely on the user's computer, partly on the user's computer, as a stand-alone software package, partly on the user's computer and partly on a remote computer or entirely on the remote computer or server. In the latter scenario, the remote computer may be connected to the user's computer through any type of network, including a local area network (LAN) or a wide area network (WAN), or the connection may be made to an external computer (for example, through the Internet using an Internet Service Provider). In some embodiments, electronic circuitry including, for example, programmable logic circuitry, field-programmable gate arrays (FPGA), or programmable logic arrays (PLA) may execute the computer readable program instructions by utilizing state information of the computer readable program instructions to personalize the electronic circuitry, in order to perform aspects of the present invention.

Aspects of the present invention are described herein with reference to flowchart illustrations and/or block diagrams of methods, apparatus (systems), and computer program products according to embodiments of the invention. It will be understood that each block of the flowchart illustrations and/or block diagrams, and combinations of blocks in the flowchart illustrations and/or block diagrams, can be implemented by computer readable program instructions.

These computer readable program instructions may be provided to a processor of a general purpose computer, special purpose computer, or other programmable data processing apparatus to produce a machine, such that the instructions, which execute via the processor of the computer or other programmable data processing apparatus, create means for implementing the functions/acts specified in the flowchart and/or block diagram block or blocks. These computer readable program instructions may also be stored in a computer readable storage medium that can direct a computer, a programmable data processing apparatus, and/or other devices to function in a particular manner, such that the computer readable storage medium having instructions stored therein comprises an article of manufacture including instructions which implement aspects of the function/act specified in the flowchart and/or block diagram block or blocks.

The computer readable program instructions may also be loaded onto a computer, other programmable data processing apparatus, or other device to cause a series of operational steps to be performed on the computer, other programmable apparatus or other device to produce a computer implemented process, such that the instructions which execute on the computer, other programmable apparatus, or other device implement the functions/acts specified in the flowchart and/or block diagram block or blocks.

The flowchart and block diagrams in the Figures illustrate the architecture, functionality, and operation of possible implementations of systems, methods, and computer program products according to various embodiments of the present invention. In this regard, each block in the flowchart or block diagrams may represent a module, segment, or portion of instructions, which comprises one or more executable instructions for implementing the specified logical function(s). In some alternative implementations, the functions noted in the block may occur out of the order noted in the figures. For example, two blocks shown in succession may, in fact, be executed substantially concurrently, or the blocks may sometimes be executed in the reverse order, depending upon the functionality involved. It will also be noted that each block of the block diagrams and/or flowchart illustration, and combinations of blocks in the block diagrams and/or flowchart illustration, can be implemented by special purpose hardware-based systems that perform the specified functions or acts or carry out combinations of special purpose hardware and computer instructions.

It will be understood from the foregoing description that modifications and changes may be made in various embodiments of the present invention without departing from its true spirit. The descriptions in this specification are for purposes of illustration only and are not to be construed in a limiting sense. The scope of the present invention is limited only by the language of the following claims. 

What is claimed is:
 1. A method of servicing database requests using subsets of canonicalized tables, the method comprising: maintaining a canonical table repository of canonicalized tables, wherein each canonicalized table is a transformed version of a table previously retrieved from a database; receiving, from a client computing system, a request for a table from the database; generating a description of a canonical version of the requested table; determining that the canonical version of the requested table is a subset of a canonicalized table in the canonical table repository; and in response to determining that the canonical version of the requested table is a subset of the canonicalized table in the canonical table repository: transforming the canonicalized table containing a superset of the canonical version of the requested table based on the received request for the table; and providing, to the client computing system, the transformed canonicalized table containing the superset of the canonical version of the requested table.
 2. The method of claim 1, wherein determining that the canonical version of the requested table is a subset of the canonicalized table in the canonical table repository comprises determining that the canonical version of the requested table does not match any canonicalized table in the canonical table repository;
 3. The method of claim 1, wherein determining that the canonical version of the requested table is a subset of a canonicalized table in the canonical table repository comprises determining that the canonical version of the requested table is a subset of a combination of at least two canonicalized tables in the canonical table repository.
 4. The method of claim 1, wherein determining that the canonical version of the requested table is a subset of a canonicalized table in the canonical table repository comprises matching each column and row in the canonical version of the requested table to columns and rows in the canonicalized table in the canonical table repository.
 5. The method of claim 1, wherein transforming the canonicalized table containing the superset of the canonical version of the requested table based on the received request for the table comprises extracting the subset of the canonicalized table in the canonical table repository to generate the requested table.
 6. The method of claim 1, wherein transforming the canonicalized table containing the superset of the canonical version of the requested table based on the received request for the table comprises one selected from a group consisting of repositioning at least one column and repositioning at least one row in the canonicalized table.
 7. The method of claim 1, wherein providing, to the client computing system, the transformed canonicalized table containing the superset of the canonical version of the requested table bypasses retrieving the requested table from the database.
 8. An apparatus for servicing database requests using subsets of canonicalized tables, the apparatus comprising a computer processor, a computer memory operatively coupled to the computer processor, the computer memory having disposed within it computer program instructions that, when executed by the computer processor, cause the apparatus to carry out the steps of: maintaining a canonical table repository of canonicalized tables, wherein each canonicalized table is a transformed version of a table previously retrieved from a database; receiving, from a client computing system, a request for a table from the database; generating a description of a canonical version of the requested table; determining that the canonical version of the requested table is a subset of a canonicalized table in the canonical table repository; and in response to determining that the canonical version of the requested table is a subset of the canonicalized table in the canonical table repository: transforming the canonicalized table containing a superset of the canonical version of the requested table based on the received request for the table; and providing, to the client computing system, the transformed canonicalized table containing the superset of the canonical version of the requested table.
 9. The apparatus of claim 8, wherein determining that the canonical version of the requested table is a subset of the canonicalized table in the canonical table repository comprises determining that the canonical version of the requested table does not match any canonicalized table in the canonical table repository;
 10. The apparatus of claim 8, wherein determining that the canonical version of the requested table is a subset of a canonicalized table in the canonical table repository comprises determining that the canonical version of the requested table is a subset of a combination of at least two canonicalized tables in the canonical table repository.
 11. The apparatus of claim 8, wherein determining that the canonical version of the requested table is a subset of a canonicalized table in the canonical table repository comprises matching each column and row in the canonical version of the requested table to columns and rows in the canonicalized table in the canonical table repository.
 12. The apparatus of claim 8, wherein transforming the canonicalized table containing the superset of the canonical version of the requested table based on the received request for the table comprises extracting the subset of the canonicalized table in the canonical table repository to generate the requested table.
 13. The apparatus of claim 8, wherein transforming the canonicalized table containing the superset of the canonical version of the requested table based on the received request for the table comprises one selected from a group consisting of repositioning at least one column and repositioning at least one row in the canonicalized table.
 14. The apparatus of claim 8, wherein providing, to the client computing system, the transformed canonicalized table containing the superset of the canonical version of the requested table bypasses retrieving the requested table from the database.
 15. A computer program product for servicing database requests using subsets of canonicalized tables, the computer program product disposed upon a computer readable medium, the computer program product comprising computer program instructions that, when executed, cause a computer to carry out the steps of: maintaining a canonical table repository of canonicalized tables, wherein each canonicalized table is a transformed version of a table previously retrieved from a database; receiving, from a client computing system, a request for a table from the database; generating a description of a canonical version of the requested table; determining that the canonical version of the requested table is a subset of a canonicalized table in the canonical table repository; and in response to determining that the canonical version of the requested table is a subset of the canonicalized table in the canonical table repository: transforming the canonicalized table containing a superset of the canonical version of the requested table based on the received request for the table; and providing, to the client computing system, the transformed canonicalized table containing the superset of the canonical version of the requested table.
 16. The computer program product of claim 15, wherein determining that the canonical version of the requested table is a subset of the canonicalized table in the canonical table repository comprises determining that the canonical version of the requested table does not match any canonicalized table in the canonical table repository;
 17. The computer program product of claim 15, wherein determining that the canonical version of the requested table is a subset of a canonicalized table in the canonical table repository comprises determining that the canonical version of the requested table is a subset of a combination of at least two canonicalized tables in the canonical table repository.
 18. The computer program product of claim 15, wherein determining that the canonical version of the requested table is a subset of a canonicalized table in the canonical table repository comprises matching each column and row in the canonical version of the requested table to columns and rows in the canonicalized table in the canonical table repository.
 19. The computer program product of claim 15, wherein transforming the canonicalized table containing the superset of the canonical version of the requested table based on the received request for the table comprises extracting the subset of the canonicalized table in the canonical table repository to generate the requested table.
 20. The computer program product of claim 15, wherein transforming the canonicalized table containing the superset of the canonical version of the requested table based on the received request for the table comprises one selected from a group consisting of repositioning at least one column and repositioning at least one row in the canonicalized table. 